A Southwest Airlines flight attendant allegedly lost two teeth after a passenger assault, and it illustrates a growing trend of unruly behavior on flights

• Southwest Airlines said a passenger was verbally and physically abusive toward a flight attendant on Sunday.
• A flight-attendants union says 477 incidents have occured on Southwest Airlines' flights.
• The Federal Aviation Administration warned instances of unruly behavior on flights are increasing.

A flight attendant for Southwest Airlines was assaulted over the weekend and lost two teeth from the incident, according to a letter a flight-attendant union sent to the company's CEO, Gary Kelly, on Monday.

The letter, from the Transport Workers Union of America local 556 (TWU), said there have been 477 incidents of violence and unruly behavior on Southwest Airlines flights between April 8 and May 15. Earlier in the month, the Federal Aviation Administration (FAA) said it had received 2,500 reports of unruly passengers since January.

"This unprecedented number of incidents has reached an intolerable level, with passenger non-compliance events also becoming more aggressive in nature," the union wrote. "Today's traveling environment requires a new level of firmness in both tone and direction to ensure proper control in the cabin of our aircraft as the attitudes and behaviors of the flying public have, unfortunately, declined."

A Southwest Airlines spokesperson confirmed the incident occured on a flight from Sacramento to San Diego on Sunday morning.

"The passenger repeatedly ignored standard in-flight instructions (tray table in upright position, seat belt, etc.) and became verbally and physically abusive upon landing," the spokesperson said. "We do not condone or tolerate verbal or physical abuse of our Flight Crews, who are responsible for the safety of our passengers."

The spokesperson told Insider the company is working with the FAA to improve safety measures for flight attendants and passengers. The passenger, who was identified as a 28-year-old woman, was taken into police custody and has been charged with felony battery, USA Today reported.

The incident is just one of many to occur on airplanes in the past few months. Earlier this month, the FAA said it was seeing a spike of unruly and aggressive behavior on airlines, citing moments when passengers hit, yelled, and shoved flight attendants. The agency proposed fines of up to $15,000 for five passengers accused of interfering with and assaulting flight attendants.

Flight attendants told Insider's Allana Akhtar that the pandemic has made passengers increasingly non-compliant and aggressive, especially when it came to enforcing the federally mandated mask policy for airlines. While the CDC lifted the mask mandate for fully vaccinated people in many spaces, customers are still required to wear masks on public aircrafts.

In its letter, the flight-attendants union called for increased penalties and restrictions for passengers who demonstrate "egregious behavior," as well as an increase in the number of federal air marshals on flights.

"The last year has brought many unknowns, and much has been out of our control," the union said. "Please keep your crews in mind and understand the impact of today's environment on our Crews' working conditions."